Advanced Testing for Cardiovascular Disease: Examining Lipoproteins
Dicken Weatherby, ND
Heart disease is still the No. 1 killer of men and women in the U.S. According to the National Center for Health Statistics, in 2005, 25.6 million “non-institutionalized” adults were diagnosed with heart disease in the U.S. (Pleis and Lethbridge-Çejku, 2006). The American Heart Association reported that cardiovascular disease “claimed 871,500 lives in 2004 (36.3% of all deaths, or 1 of every 2.8 deaths)” (online posting), and 724,500 of those deaths were in people older than age 65.
Heart disease is a major cause of morbidity in our aging population, but unfortunately the majority of heart disease is silent and asymptomatic, which presents a problem for the preventive approach of naturopathic medicine. Most physicians try to predict a patient’s chance of developing heart disease by looking at the cholesterol tests found on the lipid panel in the standard blood chemistry screen. New evidence shows that doctors who rely solely on these tests as a predictor of a patient’s chance of suffering from heart disease are not doing everything they can.
The Lipid Panel
Ask yourself these questions: Is it possible to have a low cholesterol level and still have a heart attack? Is it possible to live to the ripe old age of 90 with high cholesterol? The answer to both questions is yes. Many risk factors are associated with the development of heart disease, but most doctors place too much significance on blood cholesterol levels, at the gamble of the many other risk factors at play (see Table 1).
A routine lipid panel includes four tests:
- Total cholesterol
- Low Density Lipoprotein (LDL), which is determined by a mathematical calculation, not by direct measurement
- High Density Lipoprotein (HDL), which is actually measured.
Relying on these four tests is a serious limitation, especially when research has shown that the tests on a routine lipid panel can help identify only 40% of people with coronary artery disease (Superko, 1998). Unless a patient has cholesterol levels that are off the charts, you will be unsure of the role cholesterol is playing in their heart disease risk if you rely on the standard cholesterol tests. In most cases, it would actually be better to test for lipoproteins rather than the lipids.
Role of Lipoproteins
It is beyond the scope of this article to go into the biochemistry of cholesterol, but think of the cholesterol molecule as being carried in the bloodstream on the back of various lipoproteins. Some lipoproteins (LDL) are destined to deliver cholesterol to the cells or arterial plaque, while others (HDL) take cholesterol from the cells or plaque back to the liver for disposal or recycling.
Lipoproteins are not discrete homogenous molecules, but are composed of a mixture of particles that vary in size and density. Each particle or lipoprotein subclass has a unique role in increasing or decreasing the risk of heart disease. LDL and HDL are actually bundles of these particles. The relationships between levels also have significance. For example, knowing that a patient’s LDL is above 140mg/dl is really not enough, because you don’t know whether the relative ratios of the different particles in the LDL increase or decrease the risk for heart disease.
HDL is also composed of different subclasses of lipoprotein, according to the size and density of the particles. Large particles (HDL2) are most useful in extracting cholesterol from the cells. Small particles (HDL3) are pretty much useless.
Another Test: VAP
Individual lipoprotein testing has been around for a number of years, but has been underutilized due to the cost and availability of the test. In 2003, a new test emerged called the Vertical Auto Profile or VAP. The test was developed by Dr. Jere Segrest, director of the Atherosclerosis Research Unit at the University of Alabama-Birmingham. The test is performed like other blood lipid tests, but the results on the VAP test report go beyond the standard four. The test directly measures LDL, HDL, VLDL, total cholesterol and triglyceride levels. The test also measures the following:
- LDL particle density (clusters of small, dense LDL greatly increase the risk of cardiovascular disease)
- All the important lipoprotein subclasses:
- HDL2, the most protective form of HDL.
- HDL3, not as protective as HDL2.
- Intermediate Density Lipoproteins (IDLs). These often are elevated in people with a family history of diabetes.
- Very Low Density Lipoproteins (VLDL1, VLDL2, VLDL3). Knowing the different fractions of VLDL is important because high levels of VLDL3 put patients at a greater risk of cardiovascular disease.
- Lipoprotein (a) (Lp(a)), high levels of which are a very strong risk factor for heart attacks and strokes.
The VAP test also provides detailed information about the different risk factors for heart disease by looking at ratios between lipoprotein subclasses and the various size and density patterns that exist within them. You will know, for instance, that a patient with a pattern of small, dense LDL particles (known as “pattern B”) has a much higher risk of heart disease than a patient with a pattern of large, less dense LDL particles (“pattern A”). Excessive quantities of small, dense LDL particles have been shown to triple the risk of heart attacks, and when they are present with high total cholesterol and increased levels of C-reactive protein, the patient is six times more likely to have a heart attack (St-Pierre et al., 2001).
The VAP test is a tremendous advancement in lipid blood testing. While knowing patients’ VAP test results is very important, there are other tests that you should be running alongside it to get a comprehensive assessment of patients’ cardiovascular disease risk. These tests include homocysteine (I like to see levels below 7.2µmol/L), C-reactive protein (I like to see levels below 0.55mg/L in men and 1.5mg/L in women) and fibrinogen (I like to see levels between 200 and 300mg/dL).
Risk Factors for the Development of Heart Disease
- Excessive alcohol consumption
- Increased body mass index (increased body fat to lean muscle ratio)
- Low HDL
- High triglycerides
- High LDL
- High total cholesterol
- Lack of exercise
- Increased homocysteine
- Increased C Reactive Protein
- Increased fibrinogen
- Increased hemoglobin A1C
In conclusion, running the VAP test as well as the other mentioned blood tests on patients will provide a far greater opportunity to identify, prevent, treat and monitor heart disease than standard lipid testing. I highly recommend using these tests with any patient that presents with a family history of heart disease, Type II diabetes or high blood pressure, or a strong risk of heart disease. These tests can also be an important part of a treatment plan for patients who have had a heart attack, suffer from angina or have had some kind of cardiac surgery to relieve blockages to the coronary arteries.
Dicken Weatherby, ND is based in southern Oregon. A graduate of NCNM, Dicken is co-author of the bestselling book Blood Chemistry and CBC Analysis-Clinical Laboratory Testing from a Functional Perspective. He has self-published seven other books in the field of alternative medical diagnosis, has created numerous information products, and runs a number of successful Web sites (www.BloodChemistryAnalysis.com, www.Health-E-Marketing.com and www.StrawBale.com). He is involved in research, writing and consulting, and teaches functional diagnosis seminars in both the U.S. and his native country, the U.K.